论文部分内容阅读
This paper describes a method using both reduced pressure chemical vapor deposition (RPCVD) and ultrahigh vacuum chemical vapor deposition (UHVCVD) to grow a thin compressively strained Ge film.As the first step,low temperature RPCVD was used to grow a fully relaxed SiGe virtual substrate layer at 500℃ with a thickness of 135 nm,surface roughness of 0.3 nm,and Ge content of 77%.Then,low temperature UHVCVD was used to grow a high quality strained pure Ge film on the SiGe virtual substrate at 300℃ with a thickness of 9 nm,surface roughness of 0.4 nm,and threading dislocation density of～105 cm-2.Finally,a very thin strained Si layer of 1.5-2 nm thickness was grown on the Ge layer at 550℃ for the purpose of passivation and protection.The whole epitaxial layer thickness is less than 150 nm.Due to the low growth temperature,the two-dimensional layer-by-layer growth mode dominates during the epitaxial process,which is a key factor for the growth of high quality strained Ge films.
This paper describes a method using both reduced pressure chemical vapor deposition (RPCVD) and ultrahigh vacuum chemical vapor deposition (UHVCVD) to grow a thin compressively strained Ge film. As the first step, low temperature RPCVD was used to grow a fully relaxed SiGe virtual substrate layer at 500 ° C with a thickness of 135 nm, surface roughness of 0.3 nm, and Ge content of 77%. Then, low temperature UHVCVD was used to grow a high quality strained pure Ge film on the SiGe virtual substrate at 300 ° C with a thickness of 9 nm, surface roughness of 0.4 nm, and threading dislocation density of ~ 105 cm-2.Finally, a very thin strained Si layer of 1.5-2 nm thickness was grown on the Ge layer at 550 ° C. for the purpose of passivation and protection. The whole epitaxial layer thickness is less than 150 nm. Due to the low growth temperature, the two-dimensional layer-by-layer growth mode dominates during the epitaxial process, which is a key factor for the growth of high quality strained Ge films.